Compact heat exchanger



Jan. 18, 1966 c. D. WARE 3,229,764

COMPACT HEAT EXCHANGER Filed May 11. 1962 2 Sheets-Sheet l INVENTOR. CHESTER D. WARE A TTORNEYS Jan. 18, 1966 C. D. WARE COMPACT HEAT EXCHANGER 2 Sheets-Sheet 2 Filed May 11, 1962 FIG.3

INVENTOR. CHESTER D. WARE ATTORNEYS.

United States Patent 3,229,764 COMPACT HEAT EXCHANGER Chester D. Ware, La Crosse, Wis, assignor to The Trane Company, La Crosse, Wis, a corporation of Wisconsin Filed May 11, 1962, Ser. No. 193,926 4 Uranus. (Cl. 165-167) This invention relates generally to heat exchangers and more particularly to compact brazed plate fin type exchangers.

It is an object of this invention to provide a brazed heat exchanger which is more compact, more efficient, and readily assembled.

Another object of the invention is to provide a brazed heat exchanger which has the headers mounted internally to reduce the number of supply and return connections required and provide improved fluid and temperature distribution.

A third object of the invention is to provide a brazed heat exchanger in which the supply and return connections are centrally located on the face of the heat exchanger.

A further object of the invention is to provide a compact brazed heat exchanger in which the headers for one heat exchange fluid are located in the flow path of a second heat exchange fluid.

A still further object of the invention is to provide a compact brazed evaporator which has the headers internally mounted to allow the use of a very thin refrigerant passage.

A sixth object of the invention is to provide a compact brazed evaporator which has the headers mounted centrally and internally to eliminate space normally lost because of end header connections.

Other objects and advantages of my invention will be clearly apparent as the specification proceeds to describe the invention with reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view with a portion broken away to show my new and improved heat exchanger;

FIGURE 2 is a cross-section through one of the refrigerant inlet sections of the heat exchanger shown in FIG- URE l; and

FIGURE 3 is an exploded view in partial schematic to show the flow of heat exchange fluid through the heat exchanger.

Looking now at the drawings, a two fluid heat exchanger is illustrated. For the sake of discussion, a brazed aluminum plate fin type evaporator will be described. It is obvious that the hereinafter described heat exchanger can be employed for other purposes such as oil cooling, milk cooling, etc. Further, the heat exchanger may be constructed from other brazable materials such as stainless steel or copper.

The preferred embodiment shown in FIGURES l-3 basically consists of a plurality of refrigerant passages and a plurality of air passages 12. Refrigerant passages 10 are separated from air passages 12 by conduit means such as header blocks 14 located within the air passages and receive refrigerant through tube stubs 16 from a refrigerant distributor (not shown). A suction or return refrigerant manifold 18 is employed to return refrigerant to the refrigeration compressor (not shown).

Refrigerant passages 11) are enclosed by front and back bar members 20 and end bar members 22. An imperforate separator or partition member 24 is centrally located within the parting sheets 25 of refrigerant passage 10 to divide the flow of refrigerant from the inlet to the outlet. A plurality of fin members 26 are employed within the refrigerant passage to increase the heat transfer efliciency. The construction of the fin members may be employed, if desired.

Located on both sides of the header blocks 14 in the air passages 12 are corrugated fin members 28 to enhance the heat transfer between the refrigerant passages and the air passages. The type and shape of the fin members 28 being merely illustrative and other comparable fin members may be employed, if desired. Channel strips 30 closing the ends of the air passages are primarily for rigidity, especially during the brazing operation. It is obvious that channel strips 30 can be eliminated without substantially affecting the performance of the heat exchanger since fin members 28 can block off the ends of the air passages, if such is desired.

The top and bottom air passages 12 of the heat exchanger have fin members 28 which are reduced in height so that the heat transfer in these passages is approximately equal to one-half the heat transfer affected in the other air passages. Obviously, this construction provides maximum use of space and surface since these top and bottom air passages have refrigerant passages 10 only on one side.

Looking now to FIGURE 3, the flow of heat exchange fluid through the heat exchanger will be explained. In FIGURE 3 one circuit has been shown with the refrigerant passages cut through and the elements exploded to show the passage of refrigerant through the heat exchanger.

As previously pointed out, header blocks 14 are integrally brazed into the air passages 12. Preferably these blocks will be provided with four openings 32 therein for the passage of refrigerant. Appropriate openings in header blocks 14 are closed when the above mentioned four openings are not required. The number of openings in header blocks is merely exemplary and other numbers of openings may be used within the scope of the invention.

In operation, air will pass through the air passages 12 substantially normal to the flow of refrigerant through the refrigerant passages 10. Preferably five air passage sections 34, 36, 38, 40 and 42 with refrigerant passages therebetween are employed for one complete refrigerant circuit. Other numbers of passage sections can be employed Within the scope of the invention.

Refrigerant is supplied through inlet opening 35 into header block 14 of air passage section 36 and passes into the first two openings 32. From openings 32 the refrigerant passes upwardly into refrigerant passage 10, laterally around both ends of the partition member 24 and into the rear set of openings 32. The refrigerant then passes through the rear set of openings 32 into the refrigerant passage 10 between air passage sections 36 and 38. The refrigerant then passes laterally around both ends of partition member 24 and into the pair of openings 32 in the front portion of the air passage section 38. From the openings 32 in the air passage section 38 the refrigerant flows into the front portion of refrigerant passage 10 between air passage sections 38 and 40, flows laterally around both ends of partition member 24 and into openings 32 in the rear of air passage section 40. The refrigerant then passes into the rear portion of refrigerant passage 10 between air passage sections 40 and 42, flows laterally around both ends of partition member 24, and into openings 32 in the front portion of air passage section 42. The refrigerant is then delivered to return manifold 18 through opening 44 in header block 14 from where it is returned to the suction side of a refrigeration compressor.

It should be noted that openings 46 (FIGURE 2) are provided between openings 32 in the header block portion which is in communication with the inlet tube stubs and the outlet tube stubs 48. This allows the refrigerant to be evenly supplied to and extracted from the various composite circuits of the heat exchanger.

FIGURE 3 illustrates only one circuit and it is obvious that an identical circuit is used below that shown with the outlet opening 44 being common to both circuits. This arrangement can be repeated as many times as desirable in order to obtain the desired capacity. In the heat exchanger shown in FIGURE 1, four refrigerant circuits are shown. These four circuits employ only two outlet connections for the discharge of refrigerant into the return header 18.

As mentioned beforehand, the disclosed heat exchanger is a brazed heat exchanger. As is well known in the art, the enumerated elements are stacked, clamped, and brazed in any suitable manner such as a salt bath. It should be noted that header blocks 14 are not only serve as distribution members but also serve to strengthen the heat exchanger during clamping and brazing so that the securing pressure on the stack does not collapse the heat exchanger.

Normally after brazing the headers have to be welded or otherwise secured to the heat exchanger. In the disclosed heat exchanger, since the headers are internally connected, it is merely a matter of securing the inlet stubs 16, outet stubs 48, and return manifold 18 in position and the heat exchanger is ready to be placed in operation in a refrigeration circuit.

The disclosed invention has many advantages not present in other plate fin type heat exchangers. The integral centrally located header construction avoids the use of external headers, eliminates the wasteful use of space at the ends of the heat exchanger due to end header construction, allows the air passage fin members to be used as block offs for the end of the heat exchanger, and allows the use of a new and improved refrigerant circuiting scheme. The new and improved refrigerant circuiting scheme provides better fluid and temperature distribution, improved heat transfer performance with the improved fluid distribution, requires fewer inlet and outlet connections, and provides generally lower pressure drops. The internal header blocks in conjunction with the refrigerant circuiting provide a very thin refrigerant passage construction and, at the same time, allows the use of a large outlet connection to readily remove the refrigerant from the heat exchanger. This provides a more compact exchanger by using thinner passages. The disclosed heat exchanger construction allows the use of a portion of the air passage as a feed means for the refrigerant from one refrigerant passage to another thereby allowing the use of a minimum number of inlet and outlet connections. The header construction also allows easy alignment of the headers for the purpose of brazing and at the same time provide structural strength to the heat exchanger during brazing and for resistance to operational stresses. Also, the use of a reduced number of refrigerant inlets allows the employment of a refrigerant distributor which is simplified and provides maximum performance.

Although I have described in detail the preferred embodiment of my invention, I contemplate that many changes may be'made without departing from the scope or spirit of my invention and I desire to be limited only by the claims.

I claim: a

1. A plate type heat exchanger having a front side and a rear side comprising in combination: a plurality of generally planar fluid passages disposed in spaced generally parallel superposed relationship adapted to conduct a first heat exchange fluid; said spaced passages defining flow paths therebetween for conducting a second heat exchange fluid in a direction between the front and rear sides of said heat exchanger; each passage of said passages comprising a pair of metallic plates disposed in spaced generally parallel superposed relationship, means sealingly connecting said spaced plates of each pair at their peripheries, an elongated partition within said passage extending from one plate to the other plate dividing said passage into a front portion and a rear portion, one of 7 said plates defining an inlet opening to said passage, the

other of said plates defining an outlet opening from said passage, one of said openings being disposed in front of the front side of said partition, the other of said openings being disposed behind the rear side of said partition, said partition defining a passageway remote from said openings for providing fluid communication between the front and back sides of said partition; said outlet opening of one of said passages being disposed on the opposite side of said partitions from said outlet openings of the passages on each side of said one passage; said inlet opening of said one passage being disposed on the opposite side of said partitions from said inlet openings of the passages on each side of said one passage; first conduit means leading to said inlet opening of said one passage from said outlet opening of an adjacent passage and being disposed in the space between adjacent plates of said adjacent passage and said one passage and on one side of said partitions; second conduit means leading from said outlet opening from said one passage to said inlet opening of another adjacent passage and being disposed in the space between adjacent plates of said other adjacent passage and said one passage and on the other side of said partitions whereby said one passage is connected in series with the passages on each side thereof; and each of said openings for said passages and said first and second conduit means being arranged to intersect a common plane which is generally normal to said passages and also generally normal to said elongated partitions whereby both said first and said second conduit means which are disposed in said spaces between said passages lie in said common plane and thereby present a low resistance to the passage of said second heat exchange fluid in said flow paths.

2. The heat exchanger defined by claim 1 wherein said common plane is located generally centrally of said elongated partitions.

3. The heat exchanger defined by claim 2 wherein a corrugated heat exchange fin is disposed in the flow paths between said passages arranged that the crests and troughs thereof extend from the front side to the rear side of said heat exchanger generally normally to said elongated partitions for conducting a gaseous second heat exchange fluid in heat exchange relation with the first heat exchange fluid within said passages.

4. The heat exchanger defined by claim 1 wherein there is provided means defining an outermost fluid passage disposed outwardly of and in spaced generally parallel superposed relationship with said plurality of passages; said outermost passage comprising a pair of metallic plates spaced generally in parallel superposed relationship sealingly connected at their peripheries; one of said last mentioned plates defining both the inlet and outlet opening for said outermost passage; and means connecting one of said last mentioned inlet and outlet openings in series with one of said'outlet and inlet openings respectively of the passage adjacent said outermost passage.

References Cited by the Examiner UNITED STATES PATENTS 1,825,884 10/1931 Mueller 44 2,073,023 3/1937 Obrecht 16541 X 2,222,721 11/1940 Ramsauer et a1 165137 2,617,634 11/1952 Jendrassik l65166 3,017,161 1/1962 Sloasted et al 165167 FOREIGN PATENTS 640,680 7/1950 Great Britain.

ROBERT A. OLEARY, Primary Examiner. CHARLES SUKALO, Examiner. 

1. A PLATE TYPE HEAT EXCHANGER HAVING A FRONT SIDE AND A REAR SIDE COMPRISING IN COMBINATION: A PLURALITY OF GENERALLY PLANAR FLUID PASSAGES DISPOSED IN SPACED GENERALLY PARALLEL SUPERPOSED RELATIONSHIP ADAPTED TO CONDUCT A FIRST HEAT EXCHANGE FLUID; SAID SPACED PASSAGES DEFINING FLOW PATHS THEREBETWEEN FOR CONDUCTING A SECOND HEAT EXCHANGE FLUID IN A DIRECTION BETWEEN THE FRONT AND REAR SIDES OF SAID HEAT EXCHANGER; EACH PASSAGE AND SAID PASSAGES COMPRISING A PAIR OF METALLIC PLATES DISPOSED IN SPACED GENERALLY PARALLEL SUPERPOSED RELATIONSHIP, MEANS SEALINGLY CONNECTING SAID SPACED PLATES OF EACH PAIR AT THEIR PERIPHERIES, AN ELONGATED PARTITION WITHIN SAID PASSAGE EXTENDING FROM ONE PLATE TO THE OTHER PLATE DIVIDING SAID PASSAGE INTO A FRONT PORTION AND A REAR PORTION, ONE OF SAID PLATES DEFINING AN INLET OPENING TO SAID PASSAGE, THE OTHER OF SAID PLATES DEFINING AN OUTLET OPENING FROM SAID PASSAGE, ONE OF SAID OPENINGS BEING DISPOSED IN FRONT OF THE FRONT SIDE OF SAID PARTITION, THE OTHER OF SAID OPENINGS BEING DISPOSED BEHIND THE REAR SIDE OF SAID PARTITION, SAID PARTITION DEFINING A PASSAGEWAY REMOTE FROM SAID OPENINGS FOR PROVIDING FLUID COMMUNICATION BETWEEN THE FRONT AND BACK SIDES OF SAID PARTITION; SAID OUTLET OPENING OF ONE OF SAID PASSAGES BEING DISPOSED ON THE OPPOSITE SIDE OF SAID PARTITIONS FROM SAID OUTLET OPENINGS OF THE PASSAGES 